1. Field of the Invention
The present invention relates to an image pickup device and a pattern identification apparatus.
2. Description of the Related Art
Tokens used for game machines such as slot machines installed in a game arcade are lent to players by the game arcade at a predetermined rate. The lent tokes are strictly prohibited from taking them outside the game arcade. Some players, however, receive tokens at one game arcade and bring them to another game arcade to use them at there. Then, tokens of different game arcades may be mixed at each game arcade.
Any game arcade that wants to strictly manage its own tokens must spend a long time to remove foreign tokens from tokens collected from game machines installed in the game arcade. Some game arcades employ tokens of special composition or of a special shape to reject different tokens at the slots of game machines.
The technique of employing tokens of special composition has a limitation that it can distinguish only about seven different compositions from one another at present. The technique of employing tokens of a special shape also has a limitation that it is unable to adopt extremely deformed shapes because the tokens must be passed through a counter and a hopper. Accordingly, these techniques provide limited combinations of usage. To reject foreign tokens at each game arcade located in a given area, the game arcades must cooperate together to adopt individual tokens. This involves the necessity of new tokens and large cost. Accordingly, these techniques are not practical.
At present, the most effective way to identify tokens that are specific to a given game arcade is to form a pattern that is specific to the game arcade on the tokens, read a pattern on each token, and check the read pattern. This technique is achievable with an image processing apparatus employing an image pickup device, such as that disclosed in Japanese Unexamined Patent Publication No. Hei 11-177893. The apparatus of this disclosure has an area sensor composed of a two-dimensional matrix of pixels and employs a frame reading technique that sequentially reads the area sensor line by line and carries out image processing. This apparatus needs a long processing time and is large and expensive.
Game arcades that handle many tokens need high-speed processing, and the above disclosure is incapable of achieving such high-speed processing. In addition, the large size and expensiveness of the above disclosure are impractical for game arcades.
An object of the present invention is to provide an image pickup device that operates at high speed and is manufacturable at low cost and a pattern identification apparatus employing the image pickup device.
In order to accomplish the object, a first aspect of the present invention provides an image pickup device having an area sensor composed of a two-dimensional matrix of photoelectric pixels. Each of the photoelectric pixels has a photoelectric converter for forming an optical image, a signal comparator for comparing a charge representative signal from the photoelectric converter with a reference signal and providing a resultant signal, and a signal holder for holding the resultant signal. The photoelectric pixels are connected to address lines, respectively. Required ones of the address lines are specified, and signals are read, to a data line, out of the signal holders of the photoelectric pixels that are connected to the specified address lines in response to addressing signals passed through the specified address lines.
A second aspect of the present invention provides a pattern identification apparatus employing an image pickup device. The image pickup device has an area sensor composed of a two-dimensional matrix of photoelectric pixels. Each of the photoelectric pixels has a photoelectric converter for forming an optical image, a signal comparator for comparing a charge representative signal from the photoelectric converter with a reference signal and providing a resultant signal, and a signal holder for holding the resultant signal. The photoelectric pixels are connected to address lines, respectively. Required ones of the address lines are specified, and signals are read, to a data line, out of the signal holders of the photoelectric pixels that are connected to the specified address lines in response to addressing signals passed through the specified address lines. The specified address lines correspond to concentric circles defined on a target of disk shape. The target is identified according to the read signals that represent the concentric circles defined on the target.
A third aspect of the present invention provides the pattern identification apparatus of the second aspect with a path for moving each target with respect to the area sensor at a constant speed. The address lines to be specified are determined by detecting a first one among the photoelectric pixels that first provides an image of the target, by finding, on the area sensor, a relative center that corresponds to the center of the target according to the position of the first photoelectric pixel and the moving speed of the target, and by using the relative center.
A fourth aspect of the present invention provides an identification apparatus having a material identification unit for identifying the material of a target moving along a path and a pattern identification unit for identifying patterns on the target. The material identification unit has a material sensor for providing an output that represents the material of the target, a speed sensor for providing an output that represents the speed of the target moving along the path, and a material identifying unit for identifying the material of the target according to the outputs of the material sensor and speed sensor. The pattern identification unit has an area sensor having a two-dimensional matrix of photoelectric pixels. Each of the photoelectric pixels has a photoelectric converter for forming an optical image, a signal comparator for comparing a charge representative signal from the photoelectric converter with a reference signal and providing a resultant signal, and a signal holder for holding the resultant signal. The photoelectric pixels are connected to address lines, respectively. The pattern identification unit specifies required ones of the address lines. Signals are read, to a data line, out of the signal holders of the photoelectric pixels that are connected to the specified address lines in response to addressing signals passed through the specified address lines. The specified address lines correspond to concentric circles defined on the target. The pattern identification unit identifies the target according to the read signals that represent the concentric circles defined on the target.
According to the first aspect, the photoelectric converter of each photoelectric pixel forms an optical image, the signal comparator compares a charge representative signal from the photoelectric converter with a reference signal, and the signal holder holds an output signal from the signal comparator. Among the address lines connected to the photoelectric pixels, specific ones are specified. In response to addressing signals passed through the specific address lines, signals are transferred from the signal holders addressed by the addressing signals to a data line. Instead of reading signals from all photoelectric pixels in the area sensor, the first aspect reads signals only from specific pixels in the area sensor As a result, the first aspect needs no image processing circuit because it identifies a target pattern according to specific photoelectric pixels. This technique improves a processing speed and reduces the cost of the image pickup device.
According to the second aspect, address lines corresponding to concentric circles defined on a target of disk shape are specified. In response to addressing signals passed through the specified address lines, data related to the concentric circles is read. The read data is used to correctly identify the target at high speed without image processing. The apparatus of the second aspect is manufacturable at low cost because it needs no image processing.
According to the third aspect, the position of a photoelectric pixel in the area sensor that first encounters a target and the moving speed of the target are used to find a relative center on the area sensor that corresponds to the center of the target. According to the relative center, specific address lines are specified. Even if the target is off the center of the path for moving the target, the third aspect is capable of correctly finding the center of the target and correctly obtaining data related to concentric circles defined on the target, thereby correctly identifying the target.
According to the fourth aspect, the material identification unit identifies the material of a target according to the outputs of the material sensor and speed sensor. The pattern identification unit specifies address lines corresponding to concentric circles defined on the target which has a disk shape. In response to addressing signals passed through the specified address lines, the pattern identification unit reads data related to the concentric circles, and according to the read data, correctly identifies the target at high speed without image processing.
Consequently, the fourth aspect correctly determines whether or not the target is genuine and/or the characteristics of the target according to both the material and patterns of the target.